To obtain a locking system capable of locking and unlocking multiple keys by a key having the same shape, reducing load to have many keys or worry finding out the responding key from many keys.

The keys are locked and unlocked by inserting a key having the same shape to a key 4 into a keyhole of the key, and the stopper installed in the key is pushed up, revolving and passing the ring in the hole of the stopper. By making a plurality of locks responding to the shape of the keys 4, the plurality of locks are capable of locking the unlocking by a single key 4.